One other item not to miss is to ensure the antenna is set up for Dish Network service. Most roof antennas can be set up for one of three service providers with dip switches for Dish, Direct or the Canadian service Bell. Attempt to connect a receiver that is different than the configuration needed and the receiver won't be able to communicate with the antenna. You'll need the antenna installation/user guide to set it up correctly which will probably involve removing the cover.
While you have the cover off you can also identify the coax the needs to connect directly between the inner workings of the antenna and the the primary receiver. The installation guide will help ID the coax that coax. An easy way to trace would be to disconnect the antenna end and short the center conductor to the end connector then check the coax(s) at the other end for which one has the short circuit.